nixos/gvfs: fix libmtp udev package path

As pointed out by @sigprof[1] my bump of libmtp silently broke this, as I
moved the udev files out of the bin output of the pkg.

[1]: https://github.com/NixOS/nixpkgs/pull/144290#discussion_r775266642

nixos/modules/services/desktops/gvfs.nix

@@ -54,7 +54,7 @@ in
 
     systemd.packages = [ cfg.package ];
 
-    services.udev.packages = [ pkgs.libmtp.bin ];
+    services.udev.packages = [ pkgs.libmtp ];
 
     # Needed for unwrapped applications
     environment.variables.GIO_EXTRA_MODULES = [ "${cfg.package}/lib/gio/modules" ];